Open AccessRR Lyrae pulsational temperature scales: on the consistency between different empirical relations
Author(s) -
De Santis Renato
Publication year - 2001
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2001.04618.x
Subject(s) - physics , rr lyrae variable , astrophysics , amplitude , metallicity , luminosity , consistency (knowledge bases) , stars , galaxy , mathematics , globular cluster , optics , geometry
In this paper, by assuming the equilibrium temperatures of RRab Lyrae variables defined by Carney, Storm & Jones as correct we show that temperatures derived from (B−V) colour (mean colour over the pulsational cycle calculated on the magnitude scale) transformations by Bessel, Castelli & Plez are consistent with the Carney et al. equilibrium temperatures within a probable error of δ log T e =±0.003 . As a consequence, it is shown that the pulsational temperature scale temperature–period–blue amplitude [T eff =f(P,A B )] relation provided by De Santis, who studied the (B−V) colour of about 70 stars of Lub's sample, is a suitable relation, being reddening‐ and metallicity‐free, to calculate equilibrium temperatures for RRab variables. This relation is independent of variable mass and luminosity within a large range of period‐shift from the mean period–amplitude relation valid for Lub's sample of variables. On the contrary, it is also shown that a temperature–amplitude–metallicity relation is strictly dependent on the period–amplitude relation of the sample used for calibrating it: we prove that this means it is dependent on both the mass and luminosity variations of variables.